Header

UZH-Logo

Maintenance Infos

Chemoselectivity of the Reactions of Diazomethanes with 5-Benzylidene-3-phenylrhodanine


Seyfried, M S; Linden, A; Mloston, G; Heimgartner, H (2009). Chemoselectivity of the Reactions of Diazomethanes with 5-Benzylidene-3-phenylrhodanine. Helvetica Chimica Acta, 92(9):1800-1816.

Abstract

The reactions of 5-benzylidene-3-phenylrhodanine (2; rhodanine = 2-thioxo-1,3-thiazolidin-4-one) with diazomethane (7a) and phenyldiazomethane (7b) occurred chemoselectively at the exocyclic C=C
bond to give the spirocyclopropane derivatives 9 and, in the case of 7a, also the C-methylated products 8 (Scheme 1). In contrast, diphenyldiazomethane (7c) reacted exclusively with the C=S group leading to the 2-(diphenylmethylidene)-1,3-thiazolidine 11 via [2+3] cycloaddition and a two-fold extrusion reaction. Treatment of 8 or 9b with an excess of 7a in refluxing CH2Cl2 and in THF at room temperature in the presence of [Rh2(OAc)4], respectively, led to the 1,3-thiazolidine-2,4-diones 15 and 20,
respectively, i.e., the products of the hydrolysis of the intermediate thiocarbonyl ylide. On the other hand, the reactions with 7b and 7c in boiling toluene yielded the corresponding 2-methylidene derivatives 16, 21a, and 21b. Finally, the reaction of 11 with 7a occurred exclusively at the electron-poor C=C bond, which is conjugated with the C=O group. In addition to the spirocyclopropane 23, the C-methylated 22 was formed as a minor product. The structures of the products (Z)-8, 9a, 9b, 11, and 23 were established
by X-ray crystallography.

Abstract

The reactions of 5-benzylidene-3-phenylrhodanine (2; rhodanine = 2-thioxo-1,3-thiazolidin-4-one) with diazomethane (7a) and phenyldiazomethane (7b) occurred chemoselectively at the exocyclic C=C
bond to give the spirocyclopropane derivatives 9 and, in the case of 7a, also the C-methylated products 8 (Scheme 1). In contrast, diphenyldiazomethane (7c) reacted exclusively with the C=S group leading to the 2-(diphenylmethylidene)-1,3-thiazolidine 11 via [2+3] cycloaddition and a two-fold extrusion reaction. Treatment of 8 or 9b with an excess of 7a in refluxing CH2Cl2 and in THF at room temperature in the presence of [Rh2(OAc)4], respectively, led to the 1,3-thiazolidine-2,4-diones 15 and 20,
respectively, i.e., the products of the hydrolysis of the intermediate thiocarbonyl ylide. On the other hand, the reactions with 7b and 7c in boiling toluene yielded the corresponding 2-methylidene derivatives 16, 21a, and 21b. Finally, the reaction of 11 with 7a occurred exclusively at the electron-poor C=C bond, which is conjugated with the C=O group. In addition to the spirocyclopropane 23, the C-methylated 22 was formed as a minor product. The structures of the products (Z)-8, 9a, 9b, 11, and 23 were established
by X-ray crystallography.

Statistics

Citations

6 citations in Web of Science®
6 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

3 downloads since deposited on 25 Nov 2009
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:22 September 2009
Deposited On:25 Nov 2009 14:16
Last Modified:05 Apr 2016 13:33
Publisher:Verlag Helvetica Chimica Acta
ISSN:0018-019X
Funders:F. Hoffmann-La Roche AG, Basel
Additional Information:free access at official URL
Publisher DOI:https://doi.org/10.1002/hlca.200900149
Official URL:http://www3.interscience.wiley.com/cgi-bin/fulltext/122604491/PDFSTART

Download